Weatherproof socket for electric light bulbs



Jan. 25, 1944.

E. R. KULKA WEATHERPROOF SOCKET FOR ELECTRIC LIGHT BULBS .Filed June 21. 1941 I? IZVELITOR BY Wan/$4M ATTORN EYS Patented Jan. 25, 1944 UNITED STATES PATENT OFFICE [I WEATHERPROOF SOCKET FOR ELECTRIC LIGHTBULBS Eugene B. Kulka, Mount Vernon, N. Y.

Application June 21, 194l', Serial No. 399,097 g 3 Claims. (01. 173 358) My invention relates to a new andimproved weatherproof socket for electric light bulbs.

One of the objects of my invention is to provide a socket which will eliminate the necessity of connecting the metal shell of the socket to the outer casing of the socket by means of cement.

Another object of the invention is to provide a socket which can be easily and cheaply manufactured and assembled.

Another object of the invention is to provide improved means for rigidly connecting the metal shell of the socket to the outer insulating casing of the socket, so as to prevent the metalfshell from turning or otherwise moving relative to said casing. Y

Another object of the invention is to provide improved means for preventing the central contact of the device from being bent inwardly too far.

Other objects of the invention will be stated in the annexed description and drawing which il'- lustrate a preferred embodiment thereof, it being understood that the above general statement of the objects of my invention is intended generally to explain the same but without limitation.

Fig. 1 is a vertical central section through the axis of the improved device.

Fig. 2 is a sectional view on the line 22 of Fig. 1.

Fig. 3 is a perspective view of the inner metal shell of the device.

Fig. 4 is a sectional view on the line 44 oi Fig. 3.

Fig. 5 is a perspective view of the porcelain head to which the inner end of the metal shell is connected.

Fig. 6 is a perspective view of the device shown in Fig. 5, in reversed position.

For convenience, the device will be described with reference to its vertical position which is shown in Fig. 1, although the device can be held in any position. 3

In making sockets of the known commercial weatherproof type, it is customary to locatean ordinary insulating washer of disk shape at the upper end of the metal screw shell. Water-proof cement is then applied to the upper surface of said insulating washer, and this cement fills up the space between the washer and the top of theinsulating casing. The lower ends of the respective connecting wires are then connected respectively;

to the metal screw shell and to the centralTcontact thereof. The upper endsof said connecting wires are then pulled through the holes at the up a common cut-out 8.

per en'd of the insulating shell or casing, and the casing is thus connected to said shell by means 'ofsaid cement, in order to provide water-proof connecting and sealing means. In actual practice, this connection has been very inefiicient and very often the cement leaked out when it'was heated by the lamp. i

The improved device comprises an outer shell or casing I which is made of any suitable 'insue lating material, such as Bakeliteor the like. The shell I may be provided with a clamp 2 of any conventional type, by means of which a shade canbe; supported. The inner wall of. theinsulatiing shell i is provided with an undercut or groove 3. This groove 3 extends continuously and cir-'- cumierentially around the inner wallof them sulating shell I.. The metal screw shell dis corirugated'in the usual manner, in order to pro-.

vide an internal thread, so that the base o'ithe bulb can be screwed into the metal screw shell 4 in the usual manner; At its lower end, the shell.4 is provided with an outwardly flaring flange 5, of frustoaconical shape. The rim of this flange 5 is providedjwith serratedzones 6, which are separated by intermediate uns'errated zones 1. The shell- 5 is made of the usual metal or alloy; and its flange 5 is resilient. The top wall and the upstanding wall of the shell5 are provided with g The cut-out 8 is provided with a half round extension 8, in the top wall-oi the metal shell 4. A rigid head l0, which made ot'porcelain'br other suitable insulating material; is provided with a central boss II, which fits y a nst, the wall of the cut-out 9.- As

showngin Fig. 2a part of the upstanding periphcry of thebo'ss ll projects below the top partof. the cut-out 9,'when the parts are assembled. 1 Th bottom surface of the insulating head I0 is provided with spaced ribs J2, between. which a bore [4 is located. The insulating head lll is also provided with another vertical'bore l5; 7 The top wall of the metal shell 4 is connected to the- Rfiulating headslfi. by means of "a metal eyelet t which is passed through the bore l5 and through anlaligned bore 11 which -is-provided in the top wall of the-metal shell 4. As shown in Fig. 4,.the hole 11 is provided in a, dished portion l8.of1the top wall of theshell 4. After the cyst: drical eyelet 16 has thus been passed'through the holesl5 and H, the ends of said eyeletjfif are. enlarged and said enlarged ends are forced. towards-each other, order torprpvide a1 rivet-t like clampingcon'nectidn between the metal shell Land the-insulating head l0; This clamping" pressure straightens the dished portion l8, either wholly or partially, but no objectionable convex protuberance is formed in the top wall of the shell 4. As shown in Fig. 1, after the clamping pressure of the member l6 has been applied, the top wall of the shell 4 is provided with an annular recess IS.

The metal eyelet 20 is used for connecting the base of the central metal contact 2| of the device, to the insulating head III. This metal contact is a resilient blade, of angular shape. It has a base which abuts the bottom face of the rigid insulating head l0. passed through the hole l4 and through an aligned hole of the base of the resilient blade contact 2|. The ends of the metal eyelet 20 are then enlarged and forced towards each other,

in order to provide a rivet-likeclamping (30111180? tion. Of course the central contact 2| of the device does not contact with the metal shell 4, because the cut-out 8 provides ample clearance between the central contact 2| and the metal shell 4. The base of the central contact 2| fits snugly between the ribs l2. Therefore the base of the central contact 2| is held against turning relative to the insulating head It], even though a single eyelet 20 is used for connecting the elements 2] and I0.

1 After the metal shell 4 has thus been assembled" with the'insulating head l0, before said shell 4 isassembled with the outer shell I, the pared ends of the wires 'W are rigidly connected tothe inner walls of the eyelets l6 and 20 by solder or the like. The wires W are provided with the usual exterior insulation 22.

' The top of the insulating shell I is provided withan integral head 23, and said head 23 is provided with holes through which the insulated 'wires can be pulled upwardly. The head 23 is provided with bosses 24, which extend around the holes through which the insulated wires are pulled. 'The'head 23 is provided with a depend. ing rib 25, which fits accurately in the diametral groove 26 of the head II], when the parts are assembled. The rib 25 is downwardly tapered and the groove '26 has a corresponding tapered shape, 'so'that the rib 25 fits very snugly in the groove 26, when the parts are assembled.

Therefore, when the insulated wires are pulled upwardly through the'ho'les in the head 23, the rib 25 iscaus'edto engage the groove 26, thus holding the head ill from turning relative to the shell I,- and eliminating the necessity of using cement. e ---Likewisethe rib 25 prevents the flow of water between the chambers or spaces 21. Therefore, if-any water leaks through one of the holes of the head 23, in which an insulated wire is located, said water cannot short circuit thewires within the casing l. i

,When the. assembled metal shell and its head l0, are thus pulled into position, the resilient flange yields slightly until the rim of saidfiange snaps resiliently into the groove 3. The diameter of the rim of the ,flange5 is slightly greater than the diameter of the inner wall of. the insulating shell I, below the groove 3.. Likewise, the diameter of the rim of thefiange 5 exceeds thediaineter ofthe inner wall of the groove or un dercut 3, so that the resilience of the flange 5 forces the serrations B into the insulating material of the casing I. This provides a very re-. liable "connection between the metal shell and itsfcajsing 1, so that the metal shell cannot turn This metal eyelet is is preferably a slight clearance between the bottom of the rib and the bottom of the groove 26, when the parts are assembled. Likewise, when the parts are assembled, there may be a slight clearance between the depending walls of the rib 25 and the depending walls of the groove 26. However, the parts are made with sufiicient accuracy so that the depending walls of the groove 25 preferably fit very tightly against the depending walls of the groove 26 when the parts areassembled.

The diametral rib 25 extends wholly across the bottom face of head 23. In this embodiment, only parts of the heads 23 and ill interfit to pro- ,vide a water-tight barrier between the wires,

but the invention is not limited to this, and in general, the invention covers numerous subcombinations of the complete combination illustrated herein, as said sub-combinations can be used independently of the complete combination. The rib 25 and groove 26 illustrate one means for maintaining water-tight contact between the heads l0 and 23, while providing spaced chambers 21 between said heads, but the invention is not limited to this construction, or to the use of a single rib. The use of cement is unnecessary, but the invention includes the construction claimed herein, even if cement is used as auxiliary insulating connecting means, and to fill one or both of the chambers 2'1 with an insulating filling. However, it is preferred to eliminate the use of cement. For convenience, shell I may be designated as the first shell and shell 4 may be designated as the second shell, head 23 may be designated as'the first head, and head Ill may be designated as the second head, eyelet it may be designated as the first eyelet and eyelet 20 may be designated 'as the'secondfeyelet. The parts are dimensioned so that the resilient flange 5, due to its deformation when the parts are assembled, upwardly forces the head l0, so as to hold'the walls of groove 28 forced under pressure against the upstanding inclined walls of rib 25.

This fit may be water-tight and gas-tight. When the base of the bulb is screwed into the metal shell 4, the depending inclined arm of the resilient blade contact is forced upwardly, into contact with the bottom face of boss ll. 'This boss l l acts as a stop, so that the resilient'ju'nc tion between'the base of element 2i and its depending inclined arm cannot be stressed beyond the elastic limit. This prevents the angular blade 2i from being permanently deformed. The bot- 1. -A lamp-socket comprising an outer shell made of insulating material, said outer shell hav ing a rigid head, said head having spaced bores, a metal shell located in said outer shell, said second shell having a rigid head made of insulating material, spaced wires respectively located in the bores of the head of the outer shell, a metal contact member connected to said head of the metal shell and held spaced from-said metal shell,

said wires, being respectively electrically conor ctherwisemove relativeto the casingl... There 15, nected .tosaidumetal shell and to saidcontact member, said heads having portions thereof abutting each other in water-tight contact between the points at which said wires are connected to said metal shell and said contact member, said portions wholly separating said wires inwardly of said outer shell.

2. A weather-proof socket comprising an outer shell made of rigid insulating material, an inner metal shell located in said outer shell, said outer shell having a rigid head which has an inwardly extending rigid rib, said inner metal shell having a rigid head of insulating material which has a groove with which said rib interfits in water-tight contact, said rib and said groove extending wholly across their respective heads, wires located on the respective opposite sides of said rib, one of said wires being connected electrically to said metal shell, a contact connected to the head of the metal shell and spaced from said metal shell, the other wire being connected to said contact, said interfitting groove and rib providing watertight separating means between the respective points at which said wires are respectively connected to said shell and to said contact.

3. A weather-proof socket comprising a first and outer shell made of insulating material and having a first head which has spaced bores and an internal rib which is located between said bores and which extends wholly across the inner face of the first head, a second and inner shell made of metal and having a longitudinal wall which is shaped to receive the head of a bulb, said second shell having an end-wall at the inner end of said longitudinal wall, the end-wall of said second shell and its longitudinal wall having a cut-out whose outer end is spaced inwardly from the outer end of said longitudinal wall, said second shell having a second rigid head made of insulating material, the inner wall of the second head having a groove which extends wholly across said inner wall, said internal rib interfitting with the walls of said groove from end-to-end to provide a water-tight barrier to the passage of water from one side of said rib to the other side thereof, said groovebeing locatedbetween said first bore and said second bore, a contact blade connected to said second head, said contact blade being located in said cut-out and being spaced from the second shell and extending into the interior of the second shell, wires respectively located in the first bore and in the second bore and respectively electrically connected to said inner shell and to said contact blade at opposite sides of said barrier.

EUGENE R. KULKA. 

